Ignition apparatus



March 14, 1939.

E. B. NQWOSIELSKI IGNITION APPARATUS Filed May 1, 1937 ll rum Wk. Q

INVENTOR Edward .B. Nowaaxe/sh TORNE Patented Mar. 14, 1939 UNITED STATES PATENT OFFICE to Eclipse Aviation Gorporation,

East

Orange, N. J., a corporation of New Jersey Application May -1, 1937, Serial No. 140,237

6 Claims.

This invention relates to the control of ignition current, and particularly to the insulating and shielding of the ignition current terminal (spark plug) in a high tension circuit of the type required for fuel ignition in internal combustion engines. 1

- With the increaseinthe use of radio transmitters and/or receivers on aircraft, automo biles and other vehicles driven by power developed in internal combustion engines, it has become desirable to minimize the effect of spark discharge at the terminals of the high tension ignition current cables. The common method is to provide a grounded metallic path around the cable terminal to intercept any electromagnetic emanations of radio frequency, and thus prevent their passage into a zone of interference with respect to such radio equipment.

In the evolution of a workable shielding cover for the ignition circuit terminalincluding, necessarily, not only the 'spark plug., per se, but also the point of connection between spark plug and cablemany practical difliculties arise. For

example, there is the problem of preventing curcurrence of' which would tend to defeat the fuel.

ignition producing function of the plug. This problem necessitates use of a sleeve or tube of dielectric material to separate the cable terminal from the outer metal casing. Such a sleeve or tube commonly extends beyond the plane of the cable end in both directions, for a considerable distance, and overlaps the upper. portion of the spark plug insulator, in order to complete the dielectric barrier between the high tension path and the outer shell of the plug.

Thus at least two separate, and separable insulators are .commonly employed: one for the cable terminal connection, and one for the central electrode of theplug, per se.

An object of the present invention is to eliminate one of these insulators, and to reconstruct the second insulator in such a manner that it becomes the full functional equivalent of the two elements heretofore employed.

Another object is to provide a spark plug having a single, one-piece insulator extending from its b aseto a point well beyond the point of connection with the cable terminal.

A further object is to provide a spark plug having an outer shell of one-piece construction from its cylinder engaging end to a point beyond the upper end of the one piece insulator above described, and also having openings therein which the shell 5 to a position well beyondthe lower mented to the correspondingly threaded central serve to expose a major portion of the one-piece insulator to cooling air currents without sacrificing the'shielding qualities of said shell.

These and other objects of the invention will become apparent from inspection of the follow,- ing specification when read with reference to the accompanying drawing wherein is illustrated the preferred embodiment of the invention. It is to be expressly understood, however, that the drawing is, for the purpose of illustration only, and is not designed as a definition of the limits of the inventionjreference being had to the appended claims for this purpose.

In the drawing,

Fig. l is a view in longitudinal section of a device embodying the invention;

Fig. 2 is a top plan view of the device;

Fig. 3 is a view in longitudinal section of a second embodiment; and

Fig. 4 is a bottom plan view of the device of Fig. 3.

Referring to Fig. 1 reference character 5 designates the shell of a one-piece construction including the threaded base 6, the flange portion 1 engageable with the outer surface of the cylinder bonded to the shielding element 5, an example of such nut being indicated at 52 in my application No. 57,810, filed January 6, 1936.

Reference character ll designates the onepiece insulator which, as above described, extends from a point adjacent the lower end of end of the cable, the upper portion of the bore 40 of the insulator being of suflicient diameter so as to receive the cable readily and also to receive a pair of washers l3 and M of heat resisting material such as asbestos, from which washers there passes a cable piercing pin l6 of current conducting material the heat portion of which engages the recessed upper end of the metallic plug I8 which is threaded and preferably ce- 0 portion l9 of the bore of the insulator ll. As

shown this central portion extends down nearly to the sloping shoulder 2| of the insulator which is firmly seated upon the copper gasket 22 on the correspondingly shaped ledge. 23 formed on the inner surface of the shell 3 as the means of supporting the insulator and the parts assembled therewith, as well as providing a gas tight Joint between the members II and 5. The pressure to establish the gas tightness of this joint is produced by the step of tightening the upper externally threaded ring 23 against the compressible rings 21 and 23 at least one of which is effective, as a result of pressure thus applied, to establish a moistureproof Joint between the parts ii and Ill, the latter being internally threaded to permit this tightening of the ring 26.

The electrode constructionas shown in Fig. 1 consists of a central spindle 3| having an upper portion 32 of reduced diameter adapted to be inserted through a soft metallic nipple 33 and terminates in the counterbore portion 34 of the metallic connector plug I! to which it is permanently fused, as by welding or an equivalent process, the cooperating grounded electrode 36 being of the cup shaped type having a lower portion presenting a plane surface directly under the flat base of the spindle 3| so that the spark will occur at this point which is considerably below the circular rim portion 31 which serves as a bailie between the ,two chambers 38 and 39 in which the cylinder gases may circulate to a certain extent by reason of the perforations 4| adjacent'the base portion of the electrode. The connection between the electrode and the shell 6 may be of any suitable type but as shown includes a fusible ring 43 of soft metal of good heat conducting qualities.

The electrode construction of Fig. 3 differs from that just described in two major respects:

First, in the enlargement of the spindle 3| by the addition thereto of a ring type of elec trode 32 welded or otherwise suitably integrated therewith, and secondly, in the substitution for, the cup shaped electrode of Fig. 1, of a notched sleeve type of electrode 5i adapted to be integrated through the recessed base of the shell and having the fingers 52 constituting the lower portion thereof, capable of adjustable cooperation with the cylindrical surface of the central electrode 31 by the process of flexing. said fingers 52 laterally through the instrumentality of a suitable tool inserted through the radial open ings 53 provided at angularly spaced intervals.

about the base 3 of the shell, the spacing oi. said openings 53 being such as to correspond to the spacing of the fingers 52 as indicated at Fig.4.

To facilitate the transfer of heat from the insulator ii to the shell 5 I propose to provide a sleeve 6| of copper or equivalent heat conducting material, which may be held in place by virtue of registry with the ledge 22 at its lower end as indicated at Fig. 3, the sleeve preferably extending along thesurface of the insulater i I to a point somewhat above that at which the longitudinal slots begin.

What is claimed is:

1. A spark plug comprising a'body structure, a metallic casing fitting about said body structure and apertured near the lower end thereof, and a cylindrical electrode fitting within said casing and longitudinally slotted to form fingers flexible in response to pressure exerted thereupon by way of the apertured portion of said casing.

'2. A spark plug comprising an inner body structure, a cylinder engaging part supporting said inner body structure and apertured near its lower end, and an electrode fitting within said cylinder engaging'part and longitudinally slotted to form flngers flexible in response to pressure exerted thereupon by way of the apertured portion of said cylinder engaging part.

3. A spark plug comprising an inner body structure, a cylinder engaging part supporting said inner body structure and apertured near its lower end, and an electrode longitudinally slotted to form fingers flexible in response to pressure exerted thereupon by way of the apertured portion of said cylinder engaging part said cylinder engaging part, and

4. A, spark plug comprising aninner body structure, a cylinder engaging part supporting said inner body structure and apertured near its lower end, and an electrode adjacent said cylinder engaging part and slotted to form flners flexible in response to pressure exerted thereupon'by way of the apertured portion of said cylinder engaging part.

5. A spark plug comprising a centrally disposed electrode and supporting means therefor including a core of insulating material and a cylinder engaging part apertured near its lower end, said cylinder engaging part having a surface disposed lnteriorly thereof for the retention of said core and electrode in operative interrelationship, and a flexible electrode fitting within movable toward said centrally disposed electrode, to decrease the gap therebetween, in response to pressure exerted upon said flexible electrode by way of the apertured portion of said cylinder engaging part.

6. A spark plug comprising a centrally disposed electrode and supporting means therefor including a core of insulating material and a cylinder engaging part apertured near its lower end, said cylinder engaging part adapted to retain said core and electrode in operative interrelationship, and a flexible electrode fitting within said cylinder engaging part, and movable toward said centrally disposed electrode, to decrease the gap therebetween, in response to pressure exerted upon said flexible electrode by way of the apertured portion of said cylinder engaging part.

EDWARD B. NOWOSIELSKI. 

